Photomechanical spirit duplicating process



Aug. 11, 1959 H. c. STAEHLE ETAL 2,

' PHOTOMECHANICALI SPIRIT DUPLICATING PROCESS Filed June 10, 1957 FRA/VG/BLE POL m5)? LAYER DYE LAYER SUPPORT HENRY a. STA EHLE CAROLY/V K TUP/S INVENTORS MX-M BY ATTORNEY a Aaavr nite PHOTOMECHANICAL SPIRIT DUPLICATIN PROCESS Application June 10, 1957, Serial No. 664,701

4 Claims. (Cl. 101149.4)

This invention relates to a photomechanicall spirit duplicating process wherein a spirit duplicating master element provided with a frangible overcoa-ting layer is pressed against an adhesive photographic image to bare dye-containing areas of the element and to allow prints to be made therefrom by the direct spirit duplicating process.

In carrying out the invention, a spirit duplicating master element of the usual type is provided having a layer of dye on a paper support. This element is coated on the dye-containing surface with a thin frangible hydrophilic lower alcohol-impermeable layer of an organic colloid such as carboxymethyl cellulose. A second element is provided having an adhesive photographic image such as a sheet carrying a gelatin relief image prepared by photographic means. The first-mentioned element is pressed into contact with the second with the hydrophilic coating of the first in contact withthe adhesive image of the second, and shortly thereafter the two elements are separated with the result that areas of the frangible coating adjacent to the adhesive image break away baring a corresponding imagewise distribution of the underlying dye layer from which a multiplicity of prints may be made by the usual spirit duplicating process.

In the accompanying drawing is shown at stage 1 in greatly enlarged cross-sectional view, the appearance of the special spirit duplicating master element of which layer 20 represents a support such as paper carrying the dye layer 21 and the frangible hydrophilic colloid layer 22 temporarily adhered to layer 21.

According to the process of the invention, the element of stage 1 is pressed into contact with a second element carrying a moist adhesive photographic image until the image has adhered to the hydrophilic colloid layer and then peeling the elements apart to transfer away portions of the frangible layer and to bare areas of the underlying dye layer as shown in stage 2 wherein layer 23 represents the support for the adhesive photographic image 24. The drawing at this stage shows the supported adhesive image 24 being peeled away from the frangible layer 22 carrying with it portions 25 of layer 22 adhered to image 24 and thus baring areas 26 of the underlying dye layer 22. I

The printing element produced at stage 2 is then printed by the usual spirit duplicating methods as illustrated at stage 3 by affixing the element to the drum 27 of the usual duplicating machine, wetting the element with solvent such as alcohol and rolling it into contact with paper 28 to obtain thereon the dye image 29 from the dissolved dye of area 26 of the printing element. Since the polymeric stencil 22 is impermeable to the solvent, the underlying dye does not migrate to the surface of the paper 28.

Example A spirit duplicating master sheet of the conventional type having a colored layer of a mixture of an alcohol- States Patent Patented Aug. 11, 1959 ice Ce. 5% Carboxymethyl cellulose 10 5% Saponin 2 5% Glycerin 1.2

The solution was applied so as to obtain about 0.2 to 0.4 gram of coating per square foot when dried down, and this is preferably accomplished by two applications of the solution and drying after each application. The resulting sheet appearing substantially as shown in stage 1 of the drawing now carries a very thin layer of the hydrophilic polymer.

An adhesive photographic image was then prepared, for example, in the manner described in the Yutzy et al. U.S. Patent 2,716,059, granted August 23, 1955, by exposure to a line or half-tone subject of a substantially unhardened gelatino-silver halide emulsion layer containing a mixture of tanning .and non-tanning silver halide developing agents. Development was followed by transfer of a stratum of the undeveloped emulsion areas to a paper base or preferably to a hydrophobic base such as described in the Chan et .al. U.S. Patent application Serial No. 530,638, filed August 25, 1955, comprising a paper sheet translucentized with polystyrene and coated with a gelatin layer. The resulting adhesive image, while moist, was then pressed against the special overcoated master sheet prepared above and very soon thereafter (10 to 60 seconds) the two elements were peeled apart with the result that portions of the frangible polymer layer adhered to the adhesive image and broke cleanly away from the underlying dye layer, as shown in stage 2 of the drawing. If the element carrying the adhesive image has a rather absorbent paper base, it should be quickly rolled into contact with the frangible colloid layer and allowed to remain there for 40 seconds or less to insure that the adhesive image contains sufficient moisture for good adherence to the colloid layer.

Printing of the resulting element having an imagewise distribution of the hydrophobic organic colloid on the dye layer was carried out as shown in stage 3 of the drawing by affixing it to the drum of the usual spirit duplicating machine and moistening with solvent for the dye such as methyl alcohol or a mixture of methyl and ethyl alcohols containing minor quantities of water and ethylene glycol monomethyl ether. Several hundred prints can be readily obtained using the printing element as described provided that an adequate supply of dye is present in the printing element.

The duplicating master sheet which is coated with the layer of frangible hydrophilic organic colloid can be a commercially available spirit duplicating master sheet well known in the trade having a layer of water or Water and alcohol-soluble dye or other coloring material on its surface. However, it is necessary for the best operation of our process that the colored surface of the duplicating master sheet not carry a layer of wax or other water or alcohol-repellent substance overlying the coloring material of the sheet, as in the case of certain commercial spirit duplicating master sheets, otherwise the hydrophilic colloid layer cannot be readily coated thereon from aqueous solution and the dye cannot be transferred imagewise during the final printing operation, a material suitable for use in the process of the invention can be made by coating a paper, metal, glass or other similar surface with a soft layer of a mixture of water and alcohol (methyl or ethyl alcohol) soluble dyes such as Crystal Violet and a waxy or viscous hydrophilic binder which may be a partial solvent for the dye such as a soft high molecular weight water-soluble wax, e.g.,

the polyethylene glycols available under the name Carbowax. If desired, such coatings can contain other polyhydric alcohols such as glycerine, glycol, diethylene glycol, or ether alcohols, e.g., ethylene glycol monomethyl ether, for dispersing the coloring material. Soft soaps can also be used as a binder for the coloring material.

Additional formulas for use in coating the hydrophilic alcohol-impermeable layer over the dye layer of the spirit duplicating sheet are provided below. Unless otherwise indicated, all solutions are aqueous. The compositions in the above example and those given below which contain carboxymethyl cellulose are preferred. The carboxymethyl cellulose used should be of comparatively low viscosity.

72Al0% Vinyl azidophthalate polymer (Merrill et a1. U.S. Patent application Serial No. 525,368, filed July 29, 1955) in 1% sodium carbonate.

72Cl0% Polyvinyl acetate phthalate in dilute ammonia solution.

74F5% Ammonium alginate.

Cc. 72Bl0% Vinyl azidophthalate polymer above in 1% sodium carbonate solution 7 5% Carboxymethyl cellulose 10 73Bl0% Vinyl azidophthalate polymer in 1% sodium carbonate solution 10 5% Corn starch 5 72F10% Polyvinyl acetate phthalate 10 20% Yellow dextrin 2 77C-5% Carboxymethyl cellulose 10 1% Triton X-lOO 5 76C2.5% Sodium alginate. 77H5% Carboxymethyl cellulose 10 4% Cellulose ether phthalate 2 76F5% Carboxymethyl cellulose l0 5% Copolymer methyl vinyl ether and maleic anhydride 2 78D-(A) 1.3% Sodium alginate 10 5% Carboxymethyl cellulose 4 (B) 1% Triton X-lOO. For use, mix 10 cc. of (A) above, 5 cc. (B) above, 4 cc. water.

83G5% Carboxymethyl cellulose 10 5% Saponin 2 5% Glycerin 1.2

A solution is prepared by making a slurry in water of the alginic acid, the ammonia is added to dissolve the acid and then the alcohol to increase the viscosity of the mixture. A solution is preferably coated on the support side of the sheet before application of the frangible hydrophilic colloid layer over the dye layer on the other side.

The element thus prepared having the hydrophilic polymer layer overlying the dye layer differs substantially from similar elements of the prior art; that is, a number of attempts have been made to suppress the smudging tendency of spirit duplicating master sheets by coating them with layers of wax or other hydrophobic materials. Such elements are useless in our process since the hydrophilic adhesive photographic images such as gelatin relief images will not adhere well to such hydrophobic layers during the transfer step illustrated in stage 2 of the drawing.

The adhesive photographic image which is used as described for obtaining an imagewise distribution of hydrophilic alcohol-impermeable polymer on the dye layer may be prepared in any convenient manner. For example, instead of using the method of U.S. Patent 2,716,059 for this purpose, well-known methods for producing organic colloid imbibition dye printing matrices may be employed. For example, unhardened gelatin silver halide emulsion layers may be developed with tanning developer formulas followed by washing out the untanned emulsion areas to provide a gelatin relief image. Similarly, the known peroxide etch method can be used to provide adhesive organic colloid images. Similarly, bichromated hydrophilic colloid layers of, for example, gelatin, albumin, polyvinyl alcohol, partially hydrolyzed polyvinyl acetate and cellulose esters, etc., may be used in the same manner, the exposed areas thereof providing the adhesive images.

What we claim is:

1. A method for preparing a spirit duplicating master which comprises pressing a sheet carrying a dye-containing layer and a frangible layer of hydrophilic, alcoholimpermeable organic colloid temporarily adhered to the outer surface of the dye-containing layer, against a moist adhesive photographic image until said image has adhered to said colloid layer, separating the adhesive image from the colloid layer to obtain portions of the colloid layer adhered thereto and leaving bare areas of the dyecontaining layer underlying said portions of the colloid layer.

2. The process of claim 1 wherein the frangible layer of the element includes carboxymethyl cellulose.

3. The process of claim 1 wherein the frangible layer of the element includes sodium alginate.

4. The process of claim 1 wherein the frangible layer Since the duplicating element coated with the frangible organic colloid layer as in stage 1 may have objectionable curl, this can be alleviated by application to the back of the sheet of the following composition:

of the element includes cellulose ether phthalate.

References Cited in the file of this patent UNITED STATES PATENTS 2,073,033 Szasz Mar. 9, 1937 2,398,779 Dalton et a1. Apr. 23, 1946 2,611,313 Keller et a1 Sept. 23, 1952 2,726,168 Roddin et al Dec. 6, 1955 

1. A METHOD FOR PREPARING A SPRIT DUPLICATING MASTERWHICH COMPRISES PRESSING A SHEET CARRYING A DYE-CONTAINING LAYER AND A FRANGIBLE LAYER OF HYDROPHILIC, ALCOHOLIMPERMEABLE ORGANIC COLLOID TEMPORARILY ADHERED TO THE OUTER SURFACE OF THE DYE-CONTAINING LAYER, AGAINST A MOIST ADHESIVE PHOTOGRAPHIC IMAGE UNTIL SSAID IMAGE HAS ADHERED TO SAID COLLOID LAYER, SEPARATING THE ADHESIVE IMAGE FROM THE COLLOID LAYER TO OBTAIN PORTIONS OF THE COLLOID LAYER ADHERED THERETO AND LEAVING BARE AREAS OF THE DYECONTAINING LAYER UNDERLYING SAID PORTIONS OF THE COLLOID LAYER. 